Study on Phase Transformation Orientation Relationship of HCP-FCC during Rolling of High Purity Titanium

High purity titanium (Ti) thin strip was prepared by rolling with large deformation and was characterized by the means of Transmission Electron Microscopy (TEM), selected area diffraction (SAED) pattern, high-resolution (HRTEM) analysis, as well as Transmission Kikuchi Diffraction (TKD). It is found that there are face-centered cubic (FCC) Ti laths formed within the matrix of hexagonal close packing (HCP) Ti. This shows that the HCP-FCC phase transition occurred during the rolling, and a specific orientation relationship (OR) between HCP phase and FCC phase obeys ⟨0001⟩α// ⟨001⟩FCC and {100}α//{110}FCC. The ORs of HCP-FCC phase transition are deeply studied by TKD pole figure and phase transformation matrix. It is found that the derived results via pole figure and transformation matrix are equivalent, and are consistent with TEM-SAED analysis results, which proves that these two methods can effectively characterize the ORs of HCP-FCC phase transition and predict possible FCC phase variants.

Shock-Wave Properties and Deformation-Induced Structure of Commercial-Purity Titanium

The shock compressive wave profiles of commercial-purity titanium samples under different loading conditions have been measured. The spall strength of titanium as a function of the strain rate and temperature of deformation has been found. High-rate plastic deformation mechanisms have been studied. High-rate plastic deformation under the investigated loading conditions has been shown to occur by slip and twinning. The α → ω transformation has been established to begin at 12.2 GPa.